Petroleum products and hydrocarbon liquids are commonly stored in large cylindrical tanks sealed by roofs which float upon the liquid contained within the tanks to prevent contamination of the liquid and the escape of vapors into the atmosphere. Various sealing arrangements are known in the art and are shown, for example, in U.S. Pat. Nos. 4,811,859, 4,353,477, and 5,036,995.
Many of these sealing systems, such as the one disclosed in U.S. Pat. No 4,811,859, comprise a primary or continuous seal and a secondary seal which are mounted on a rim extending upwardly from the floating roof. Both the primary seal and the secondary seal contact an inner wall surface of the cylindrical storage tank and prevent external contaminants from entering the tank and vapors from escaping the tank. The primary and secondary seals are generally mounted on a rim extending upwardly from the top of the floating roof. It is difficult to remove or replace the secondary seal from the rim without compromising the effectiveness of the primary seal, which may result in harmful vapors escaping from the tank. Therefore, there remains a need for a simple system for mounting the primary seal and the secondary seal to the floating roof which permits the removal or replacement of the secondary seal without affecting the primary seal connection and which does not require additional parts or expense in manufacturing or installation.